Transport refrigeration system monitoring methods of the prior art conventionally monitor refrigeration capacity and adequacy of refrigerant charge once the system pulls the temperature of the served cargo space "in range", i.e., when the temperature of the served cargo space approaches the selected set point temperature of the cargo space. It would be desirable, and it is an object of the present invention, to be able to monitor the operation of a transport refrigeration system for capacity and adequacy of refrigerant charge at all times, during both cooling and hot gas heating modes, and also including the initial temperature pull down of the cargo space.
Prior art transport refrigeration system monitoring methods do not detect improperly loaded cargo spaces, or shifted loads in cargo spaces which result in improper loading. Thus, in addition to providing earlier warnings and shut downs for marginal and improper operation of a transport refrigeration system, it is also an object of the invention to be able to monitor the cargo space served by a transport refrigeration system, for restricted air flow, such as caused by improper loading, or load shifting.